Optical connector

ABSTRACT

To extend the service life of a latch of a plug housing and facilitate assembly and aligning operations of an optical connector. The optical connector includes a latch provided in a cantilever form on an external surface of the optical connector and deformable for attachment/detachment with respect to an adaptor, and an excessive deformation preventing unit that prevents excessive deformation of the latch. Furthermore, the optical connector comprises: a ferrule including a flange having a largest width portion having directionality in a circumferential direction and a conical portion continuous to the front of the largest width portion; and a housing including a cavity having a cylindrical portion through which the largest width portion can pass freely, a housing unit arranged in front of the cylindrical portion for housing the largest width portion, and an inclined surface that is arranged at a junction between the cylindrical portion and the housing unit and inclines inward in the radial direction from the cylindrical portion toward the housing unit, wherein the point of the ferrule is protruded from the point of the housing by a predetermined amount and held, in the state that the ferrule is inserted into the housing from a rear end of the cylindrical portion and the largest width portion of the flange is housed in the housing unit.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/387,680, filed Mar. 24, 2006, and is based upon and claims thebenefit of priority from the prior Japanese Patent Application No.2005-086629, filed on Mar. 24, 2005; the entire contents of which areincorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to an optical connector fitted to an endof an optical fiber and attached to or detached from an adaptor.

Generally, the above type of optical connectors include one which isfixed to the adaptor by a latch projected outward in a cantilever formon an external surface of the connector.

A conventional optical connector 101 shown in FIGS. 1 and 2 includes aferrule 110 formed of a ferrule body 111 and a flange 115, and a plughousing 120. The optical connector 101 includes a latch 121 deformablefor attachment/detachment with respect to the adaptor, on the externalsurface of the plug housing 120 in the cantilever form.

In FIGS. 1 and 2, reference sign 140 denotes a spring, 150 denotes astop ring, 155 denotes a retention member, 160 denotes a clip sleeve,165 denotes a heat shrinkable tube, and 170 denotes a hood.

The optical connector is disclosed in Japanese patent No. 3066322,Japanese Patent Application Laid-Open No. H9-113762, Japanese patent No.3103773, and Japanese Patent Application Laid-Open No. H8-327855.

However, the conventional optical connector has the following problems.

That is, when the connector is attached to and detached from the adaptorrepetitively about 500 times, the latch 121 of the plug housing 120 isbroken, and cannot maintain the function as the connector.

When the connector is assembled, it is difficult to insert the ferrule110 in the plug housing 120.

Furthermore, in an aligning operation, such a state that the ferrule 110retracts and does not return to an original position occurs.

SUMMARY OF THE INVENTION

The present invention has been achieved in order to solve the aboveproblems, and one object of the present invention is to extend theservice life of the latch of the plug housing, and another object is toprovide an optical connector that can facilitate assembling and aligningoperations of the connector.

To achieve the objects, according to one aspect of the presentinvention, there is provided an optical connector that includes a latchprovided in a cantilever form on an external surface of the opticalconnector and deformable for attachment/detachment with respect to anadaptor, and an excessive deformation preventing unit that preventsexcessive deformation of the latch.

According to another aspect of the present invention, there is providedan optical connector, wherein the excessive deformation preventing unitis formed as a protrusion on the external surface of the opticalconnector, to which a free end of the latch approaches when the latchdeforms.

According to a still another aspect of the present invention, there isprovided an optical connector, comprising: a ferrule including a flangehaving a largest width portion having directionality in acircumferential direction and a conical portion continuous to the frontof the largest width portion; and a housing including a cavity having acylindrical portion through which the largest width portion can passfreely, a housing unit arranged in front of the cylindrical portion forhousing the largest width portion, and an inclined surface that isarranged at a junction between the cylindrical portion and the housingunit and inclines inward in the radial direction from the cylindricalportion toward the housing unit, wherein the point of the ferrule isprotruded from the point of the housing by a predetermined amount andheld, in the state that the ferrule is inserted into the housing from arear end of the cylindrical portion and the largest width portion of theflange is housed in the housing unit.

According to a still another aspect of the present invention, there isprovided an optical connector, wherein the largest width portion of theflange is formed in a polygonal shape in cross section, and the housingunit of the housing is formed in a polygonal shape corresponding to thelargest width portion.

According to a still another aspect of the present invention, there isprovided an optical connector, wherein the diameter of the cylindricalportion is formed equal to the diameter of a circle circumscribing tothe polygonal housing unit.

According to a still another aspect of the present invention, there isprovided an optical connector, comprising: a ferrule including a flangehaving a largest width portion having directionality in acircumferential direction and a conical portion continuous to the frontof the largest width portion; a housing including a cavity having acylindrical portion through which the largest width portion can passfreely, a housing unit arranged in front of the cylindrical portion forhousing the largest width portion, an inclined surface that is arrangedat a junction between the cylindrical portion and the housing unit andinclines inward in the radial direction from the cylindrical portiontoward the housing unit, and a support surface continuous to the housingunit and corresponding to the conical portion; and a pressing memberthat presses the largest width portion forward, when the ferrule isinserted into the housing from a rear end of the cylindrical portion,wherein the point of the ferrule is protruded from the point of thehousing by a predetermined amount and held, in the state that thelargest width portion of the flange is housed in the housing unit, andthe conical portion is pressed against the support surface correspondingthereto by the pressing member.

According to a still another aspect of the present invention, there isprovided an optical connector, wherein the pressing member is arrangedin a space between the circumference of the flange at the back of thelargest width portion and the cylindrical portion.

According to a still another aspect of the present invention, there isprovided an optical connector, comprising: a latch provided in acantilever form on an external surface of the housing and deformable forattachment/detachment with respect to an adaptor; and an excessivedeformation preventing unit that prevents excessive deformation of thelatch.

According to a still another aspect of the present invention, there isprovided an optical connector, wherein the excessive deformationpreventing unit is formed as a protrusion on the external surface of thehousing, to which a free end of the latch approaches when the latchdeforms.

According to a still another aspect of the present invention, there isprovided an optical connector, wherein the largest width portion of theflange is formed in a polygonal shape in cross section, and the housingunit of the housing is formed in a polygonal shape corresponding to thelargest width portion.

According to a still another aspect of the present invention, there isprovided an optical connector, wherein the diameter of the cylindricalportion is formed equal to the diameter of a circle circumscribing tothe polygonal housing unit.

These and other features of the present invention can be best understoodfrom the following specification and drawings, the following of which isa brief description.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects and the configuration of this invention willbecome clearer from the following description of the preferredembodiments, read in connection with the accompanying drawings in which:

FIG. 1 is a front elevation of an example of a conventional opticalconnector;

FIG. 2 is an elevational longitudinal section of FIG. 1;

FIG. 3 is a front elevation of an embodiment of an optical connectoraccording to the present invention;

FIG. 4 is an elevational longitudinal section of FIG. 3;

FIG. 5 is a perspective view of a ferrule;

FIG. 6A is a plan view of a housing;

FIG. 6B is a front elevation of the housing;

FIG. 6C is an elevational longitudinal section of the housing;

FIG. 7A is a point side end view of the housing;

FIG. 7B is a bottom side end view of the housing;

FIG. 8 is a longitudinal section of an adapter and a front elevation ofthe optical connector;

FIG. 9 is a front view of the state of a latch in a process of attachingthe optical connector to the adaptor;

FIG. 10 is a plan view of the state of the latch when the opticalconnector is attached to an adaptor;

FIG. 11 is a front elevation of FIG. 10;

FIGS. 12A and 12B are enlarged cross sections for comparing a case ofincluding an inclined face at a junction of a cylindrical portion and ahousing unit (FIG. 12A), and a case of not including the inclined face(FIG. 12B); and

FIGS. 13A and 13B are cross sections of a normal state of the opticalconnector (FIG. 13A) and a state when the ferrule is pushed in at thetime of an aligning operation.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Embodiments of the present invention will be described with reference tothe drawings.

FIG. 3 is a front elevation of an embodiment of an optical connectoraccording to the present invention, and FIG. 4 is an elevationallongitudinal section of FIG. 3. An optical connector 1 includes aferrule 10 and a housing (plug housing) 20.

The ferrule 10 includes, as shown in FIG. 5, a ferrule body 11 and aflange 15.

In the ferrule body 11, an optical fiber is inserted into a central holeand fixed thereto, and a point of the ferrule body 11 is grinded so asto suit to optical connection.

A base of the ferrule body 11 is mounted on the point of the flange 15.The flange 15 includes a largest width portion 16 in a hexagonal shapeand a conical portion 17 continuous to the front of the largest widthportion 16. A notch 18 is formed at one position on the circumference ofthe conical portion 17.

As shown in FIGS. 6A, 6B, 6C, 7A, and 7B, the plug housing 20 includes alatch 21 deformable for attachment/detachment with respect to theadaptor on an external surface thereof in a cantilever form. The plughousing 20 includes an excessive deformation preventing unit 25 thatprevents an excessive deformation of the latch 21.

The excessive deformation preventing unit 25 is formed as a protrusionon the external surface of the plug housing 20, to which a free end ofthe latch 21 approaches when the latch 21 deforms.

In the plug housing 20, a cavity 30 that passes through the oppositeends thereof is formed.

In the cavity 30 of the plug housing 20, there is formed a cylindricalportion (cylindrical surface) 31, into which the largest width portion16 of the ferrule 10 can be freely inserted. A hexagonal housing unit 33that houses the largest width portion 16 is formed in front of thecylindrical portion 31. A support surface 34 corresponding to theconical portion 17 of the flange 15 is formed in front of the housingunit 33, continuous to the housing unit 33.

The diameter of the cylindrical portion 31 is formed equal to thediameter of a circle circumscribing to the hexagonal housing unit 33.Therefore, the largest width portion 16 of the ferrule 10 can beinserted into the cylindrical portion 31 of the cavity 30, regardless ofthe angle of the largest width portion 16 with respect to a centralaxis.

On the other hand, the largest width portion 16 of the ferrule 10 cannotbe inserted into the housing unit 33 of the cavity 30, unless the angleis relatively adjusted so that the hexagonal shape of the housing unit33 agrees with the hexagonal shape of the largest width portion 16.

When the largest width portion 16 of the ferrule 10 is housed in thehousing unit 33 of the cavity 30, the conical portion 17 continuous tothe largest width portion 16 engages with and abuts against the supportsurface 34 continuous to the housing unit 33.

An inclined surface 32 that inclines inward in the radial direction fromthe cylindrical portion 31 toward the housing unit 33 is formed at ajunction of the cylindrical portion 31 and the housing unit 33 of thecavity 30.

As shown in FIGS. 3 and 4, the optical connector 1 includes a spring 40as a pressing member arranged in a space between the circumference ofthe flange 15 at the back of the largest width portion 16 and thecylindrical portion 31 of the cavity 30, when the ferrule 10 is insertedinto the plug housing 20 from the cylindrical portion 31 side.

Since the conical portion 17 is pressed on the support surface 34 by thespring 40, in the state with the largest width portion 16 being housedin the housing unit 33, the optical connector 1 holds the ferrule 10with the point thereof protruded from the plug housing 20 by apredetermined amount.

A protective tube 19 is fitted to the flange 15 of the ferrule 10, andthe ferrule 10 is inserted into the plug housing 20 from the cylindricalportion 31 side. The spring 40 is then positioned by arranging it at theback of the largest width portion 16 and by fitting a stop ring 50 tothe plug housing 20.

The optical connector 1 is assembled and integrally formed by mounting aclip ring 60 and a boot 70 on the circumference of the stop ring 50,allowing a clip 80 including a trigger lever 81 to pass over the outercircumference of the junction of the stop ring 50 and the boot 70, andfitting the clip 80 to the plug housing 20.

FIGS. 8 to 11 show one example of an adaptor 90, and indicating how theoptical connector 1 is attached and detached with respect to the adaptor90. The adaptor 90 includes a ferrule housing unit 91 that stores theferrule 10 protruding from the point of the plug housing 20 of theoptical connector 1.

The adaptor 90 includes a projection 92 that presses a protrusion 22 ofthe latch 21 downward in a process in which the optical connector 1 isinserted and the ferrule 10 is housed in the ferrule housing unit 91 toa predetermined depth. The projection 92 presses the protrusion 22downward so that the latch 21 is collapsed (deformed) once in adirection approaching to the plug housing 20.

The projection 92 releases the downward pressing towards the protrusion22 of the latch 21 at a position immediately before the ferrule 10 ishoused in the ferrule housing unit 91 to the predetermined depth. As aresult, the latch rises toward the original state due to a spring forceof the latch 21 (the deformation is restored to the original state).

The adaptor 90 includes an engaging unit 93, with which the protrusion22 engages, when the protrusion 22 passes the projection 92 and thelatch 21 rises due to its own spring force (when the deformation isrestored). Since the protrusion 22 of the latch 21 engages with theengaging unit 93, the optical connector 1 is attached to the adaptor 90.

When the optical connector 1 is detached from the adaptor 90, thetrigger lever 81 is pressed down to bring the latch 21 down, therebydetaching the protrusion 22 from the engaging unit 93 of the adaptor 90.The protrusion 22 of the latch 21 is allowed to pass below theprojection 92, and the optical connector 1 is pulled out, therebydetaching the optical connector 1 from the adaptor 90.

When the trigger lever 81 is pressed down, a free end of the latch 21abuts against the excessive deformation preventing unit 25 on the uppersurface of the plug housing 20. As a result, the latch 21 is preventedfrom deforming largely.

In other words, the excessive deformation preventing unit 25 restrictsthe collapsed amount of the latch 21, so that the latch 21 issufficiently brought down up to a height required for the protrusion 22to pass below the projection 92 of the adaptor 90, but is not broughtdown more than necessary.

As a result, even when attachment and detachment of the opticalconnector 1 with respect to the adaptor 90 is repeated, the deformedamount of the latch 21 is kept to a required amount at all times, andthe latch 21 is not largely deformed more than necessary. Accordingly,the service life of the latch 21 is extended, and resistance againstattachment/detachment of the optical connector 1 can be greatlyimproved, as compared to a conventional optical connector having noexcessive deformation preventing unit 25.

That is, in the case of the optical connector 101 shown in FIGS. 1 and2, when attachment/detachment of the optical connector 101 with respectto the adaptor is repeated 500 times, the latch 121 of the plug housing120 is broken.

On the other hand, in the case of the optical connector 1, when such anexperiment is executed that attachment/detachment of the opticalconnector 1 with respect to the adaptor 90 is repeated until the latch21 of the plug housing 20 is broken, the latch 21 was not broken, evenwhen attachment/detachment operations are repeated 3000 times.

When the optical connector 1 is to be assembled, the ferrule 10 isinserted into the plug housing 20 from the cylindrical portion 31 sideand the stop ring 50 is fitted to the plug housing 20, while pressingthe ferrule 10 in a direction of the point thereof by the spring 40.

At this time, it is necessary to insert the hexagonal largest widthportion 16 of the ferrule 10 into the hexagonal housing unit 33 of theplug housing 20, while adjusting the angle thereof.

A cylindrical portion 31 of a size circumscribing to the hexagonalhousing unit 33 is formed on this side of the housing unit 33 of theplug housing 20, at the time of an assembly operation.

In the conventional optical connector 101, as shown in FIG. 12B, thejunction of a cylindrical portion 131 and a housing unit 133 of the plughousing 120 has been connected by a plane orthogonal to the axialdirection of the plug housing 120. Therefore, at the time of assemblingthe optical connector 101, when a hexagonal largest width portion 116 ofthe ferrule 110 is inserted into a hexagonal housing unit 133 of theplug housing 120, insertion is not possible unless the angles of thesehexagonal shapes match with each other.

On the other hand, in the optical connector 1 of the present invention,as shown in FIG. 12A, the plug housing 20 includes the inclined surface32 that inclines inward in the radial direction from the cylindricalportion 31 toward the housing unit 33 at the junction of the cylindricalportion 31 and the housing unit 33. The ferrule 10 also includes theconical portion 17 in front of the hexagonal largest width portion 16continuous thereto.

Therefore, when the hexagonal largest width portion 16 of the ferrule 10is inserted into the hexagonal housing unit 33 of the plug housing 20,and it is tried to relatively adjust the angle of the ferrule 10 and theplug housing 20, the conical portion 17 of the ferrule 10 can freelyadjust the angle along the inclined surface 32 of the plug housing 20.

Consequently, at the time of assembling the optical connector 1, theoptical connector 1 can be easily assembled, even when there is someangular displacement between the hexagonal largest width portion 16 ofthe ferrule 10 and the hexagonal housing unit 33 of the plug housing 20.

In some cases, an aligning operation of the optical connector 1 isperformed for adjusting the center of the axis between the optical fiberon the adaptor 90 side and the optical fiber of the optical connector 1.In this case, after the ferrule 10 protruding from the point of theoptical connector 1 is pushed into the plug housing 20 once, the pushingforce is released. Then, the ferrule 10 returns to the originalprotruded state due to the thrust of the spring 40.

FIG. 13A shows a normal state before the ferrule 10 is pushed in theplug housing, and FIG. 13B shows a state when the ferrule 10 is pushedtherein.

When the ferrule 10 returns from the pushed state, the angle can beadjusted by the conical portion 17 of the ferrule 10 along the inclinedsurface 32 of the plug housing 20. Therefore, even when there is someangular displacement at the time of pushing the ferrule 10 in the plughousing 20, the ferrule 10 does not stay in the pushed state, andmovement to return to the normal position can be facilitated.

According to the present invention, the shape of the largest widthportion 16 in the flange 15 of the ferrule 10 is not limited to thehexagonal shape, as in the embodiment, and may be an optional polygonalshape. In this case, the shape of the housing unit 33 of the plughousing 20 that stores the largest width portion 16 can be formed in anoptional polygonal shape, matched with the shape of the largest widthportion 16.

Furthermore, according to the present invention, the shape of thelargest width portion 16 of the ferrule 10 can be formed, for example,in a shape having directionality in a circumferential direction byappropriate means. In this case, the shape of the housing unit 33 of theplug housing 20 that stores the largest width portion 16 is also formedin the shape having directionality in a circumferential direction by thesame means, matched with the shape of the largest width portion 16.

The object of the present invention is not limited to achievecompatibility between realization of extended service life of the latch21 and realization of easiness of assembly and the aligning operation ofthe optical connector 1.

That is, if it is the only object to extend the service life of thelatch 21, the inclined surface 32 of the cavity 30 is not necessary, andthe excessive deformation preventing unit 25 that prevents excessivedeformation of the latch 21 needs only to be provided. The presentinvention is realized only by this configuration.

Furthermore, if it is the only object to facilitate assembly and thealigning operation of the optical connector 1, the excessive deformationpreventing unit 25 of the plug housing 20 is not necessary, and theinclined surface 32 that inclines inward in the radial direction fromthe cylindrical portion 31 toward the housing unit 33 needs only to beformed at the junction of the cylindrical portion 31 and the housingunit 33 of the cavity 30. The present invention is realized only by thisconfiguration.

The configuration of the present invention includes the latch deformablefor attachment/detachment with respect to the adaptor, provided in acantilever form on the external surface of the connector, and theexcessive deformation preventing unit that prevents excessivedeformation of the latch. As a result, the service life of the latch ofthe plug housing can be extended.

Furthermore, according to the present invention, the optical connectorcomprises: the ferrule including the flange having the largest widthportion having directionality in a circumferential direction and theconical portion continuous to the front of the largest width portion;and the housing including the cavity having the cylindrical portionthrough which the largest width portion can pass freely, the housingunit arranged in front of the cylindrical portion for housing thelargest width portion, and the inclined surface that is arranged at ajunction between the cylindrical portion and the housing unit andinclines inward in the radial direction from the cylindrical portiontoward the housing unit, wherein the point of the ferrule is protrudedfrom the point of the housing by a predetermined amount and held, in thestate that the ferrule is inserted into the housing from a rear end ofthe cylindrical portion and the largest width portion of the flange ishoused in the housing unit. Accordingly, the assembly and the aligningoperation of the connector can be facilitated.

While preferred embodiments of the present invention have been describedabove, the foregoing description is in all aspects illustrative. It istherefore understood that numerous modifications can be devised withoutdeparting from the spirit or scope of the appended claims of theinvention.

Although an embodiment of this invention has been disclosed, a worker ofordinary skill in this art would recognize that certain modificationswould come within the scope of this invention. For that reason, thefollowing claims should be studied to determine the true scope andcontent of this invention.

1. An optical connector comprising: a plug housing having a latchprovided in a cantilever form on an external surface of the plug housingand deformable for attachment/detachment with respect to an adaptor, theplug housing having an excessive deformation preventing unit protrudingfrom the external surface of the plug housing, to which a free end ofthe latch approaches when the latch deforms, that prevents excessivedeformation of the latch.
 2. An optical connector comprising: a ferruleincluding a flange having a largest width portion having directionalityin a circumferential direction and a conical portion continuous to thefront of the largest width portion; and a housing including a cavityhaving a cylindrical portion through which the largest width portion canpass freely, a housing unit arranged in front of the cylindrical portionfor housing the largest width portion, and an inclined surface that isarranged at a junction between the cylindrical portion and the housingunit and inclines inward at a non-parallel, non-perpendicular angle tothe radial direction from the cylindrical portion toward the housingunit, wherein the point of the ferrule is protruded from the point ofthe housing by a predetermined amount and held, in the state that theferrule is inserted into the housing from a rear end of the cylindricalportion and the largest width portion of the flange is housed in thehousing unit.
 3. An optical connector comprising: a ferrule including aflange having a largest width portion having directionality in acircumferential direction and a conical portion continuous to the frontof the largest width portion; a housing including a cavity having acylindrical portion through which the largest width portion can passfreely, a housing unit arranged in front of the cylindrical portion forhousing the largest width portion, an inclined surface that is arrangedat a junction between the cylindrical portion and the housing unit andinclines inward at a non-parallel, non-perpendicular angle to the radialdirection from the cylindrical portion toward the housing unit, and asupport surface continuous to the housing unit and corresponding to theconical portion; and a pressing member that presses the largest widthportion forward, when the ferrule is inserted into the housing from arear end of the cylindrical portion, wherein the point of the ferrule isprotruded from the point of the housing by a predetermined amount andheld, in the state that the largest width portion of the flange ishoused in the housing unit, and the conical portion is pressed againstthe support surface corresponding thereto by the pressing member.
 4. Theoptical connector according to claim 3, further comprising: a latchprovided in a cantilever form on an external surface of the housing anddeformable for attachment/detachment with respect to an adaptor; and anexcessive deformation preventing unit that prevents excessivedeformation of the latch.